1. Field of the Invention
The present invention generally relates to an electronic musical instrument providing a keyboard unit in which a predetermined sound can be assigned to each of keys.
2. Prior Art
As known well, there are provided several kinds of tone-generation-task assignment methods in the electronic musical instruments providing the keyboard units. For example, there are provided a so-called last-prior-to-first assignment method and a so-called higher-pitch-prior-to-lower-pitch assignment method. According to the last-prior-to-first assignment method, the last one is selected from a plurality of keys sequentially depressed; and then, a tone-generation task is firstly assigned to the key lastly depressed. In short, the lastly depressed key is selected prior to the other keys within the plural keys sequentially depressed on a last-come first-served basis, so that its sound is generated firstly prior to the other sounds corresponding to the other keys. According to the higher-pitch-prior-to-lower-pitch assignment method, one key having a higher tone pitch is selected from a plurality of keys sequentially depressed; and then, a tone-generation task is firstly assigned to that key, so that its sound is generated firstly prior to the other sounds corresponding to the other keys whose tone pitches are lower than the key selected. The above-mentioned two methods are generally employed by the electronic musical instruments.
Further, there are provided a split performance technique and a dual performance technique each of which responds to a manner of performance employed by a performer. When employing the split performance technique, the whole key area of the keyboard is divided into two areas, i.e., a higher-pitch area and a lower-pitch area, at a predetermined tone pitch. In other words, all of the keys provided in the keyboard are classified into two sections on the basis of the predetermined tone pitch. Then, the certain tone-generation-task assignment method is carried out on each of the sections. On the other hand, when employing the dual performance technique, a plurality of tone colors can be simultaneously produced from one key depression.
Meanwhile, the conventional electronic musical instrument is designed to provide the predetermined tone-generation-task assignment method and predetermined functions regarding the tone-generation tasks. Therefore, it is not possible to change them in response to the will of the performer. Moreover, each of the aforementioned split performance technique and dual performance technique requires predetermined functions which must be provided in the electronic musical instrument in advance. Therefore, if the electronic musical instrument does not provide those functions in advance, it is not possible for the user to carry out the split performance technique and dual performance technique freely.
In the split performance technique, different tone colors are respectively used for the key areas which are divided on the basis of the predetermined tone pitch. Therefore, once the split performance technique is employed, the electronic musical instrument cannot flexibly respond to each of musical tunes to be played.